node_modules/@plotly/mapbox-gl/src/shaders/fill.fragment.glsl

#pragma mapbox: define highp vec4 color
#pragma mapbox: define lowp float opacity

void main() {
    #pragma mapbox: initialize highp vec4 color
    #pragma mapbox: initialize lowp float opacity

    gl_FragColor = color * opacity;

#ifdef OVERDRAW_INSPECTOR
    gl_FragColor = vec4(1.0);
#endif
}